Mobile non-volatile solid state storage is available as a Disk-on-Keys™ system marketed by M-systems Inc. In this system, a small key fob with a USB connector includes a flash memory module and a controller which communicates over the USB connector with a host computer. The controller emulates a disk drive to the host system.
Many electronic devices use flash memory modules for non-volatile storage of data or code.
While many electronic devices store data (e.g., cellular telephones, organizers, palm computers), interfacing with a host computer typically requires special protocols and user interfaces.
There exist digital cameras that can be connected to a USB port on a host computer and images stored in their memory can be viewed on the host computer.
Some devices, while mobile, cannot be used at all times. For example, airlines prohibit the use of cellular telephones on airplanes, which blocks access to information stored on a cellular telephone, while the airline is in flight.